Instant messaging services (IMS) have been widely used in daily lives. In Taiwan, it is found that on average, a person may spend over one hour using one or more IMS applications such as LINE®, WeChat®, Whatsapp®, etc.
In a closed network of, for example, an enterprise, an organization, a government body, etc., using an IMS application to communicate has become very common. In view of a higher security requirement for the closed network, an enterprise version of IMS application has been developed. Typically, the enterprise version of IMS application is exclusive for use by the members of a specific closed network. That is to say, non-members are not allowed to transmit data with the members using the enterprise version of IMS application.